1. Field of the Invention
The present invention relates to a method for a program-controlled telephone exchange system, particularly a private automatic branch exchange, comprising a control computer unit sequencing all exchange operations which has access to corresponding memory arrangements in which the information required therefor are stored, whereby various performance features, in conjunction with voice connections already existing, are to be set up, are activatable from a respectively authorized subscriber station.
2. Description of the Prior Art
In current telephone exchange systems, a telephone subscriber can lay claim to specific performance features from his own telephone station, and a number of performance features can be expanded by utilizing semiconductor memories and control computer units. Such performance features relate, for example, to call protection, to automatic call back, to rerouting, for offering or for a conference connection. Such services can be requested, even given seizure of the exchange devices, or can also be requested during an existing call connection. It is known to request service requests by dialing defined numbers or, respectively, code digit sequences, which differ from one another. This is involved and, particularly given long digit sequences to be augmented by check identifiers, there is a risk of faulty inputs. Another possibility of activating individual services consists of actuating specific procedure keys. Expensive special telephone stations are required in order to provide such procedure keys. If additional services are to be enabled, then the number of procedure keys would have to be correspondingly increased. This, however, would not only lead to a higher price but the easy surveyability of the existing key field would also thereby be lost.